Japanese-English language equivalence of the Cognitive Abilities Screening Instrument among Japanese-Americans.
BACKGROUND
The Cognitive Abilities Screening Instrument (CASI) was designed for use in cross-cultural studies of Japanese and Japanese-American elderly in Japan and the U.S.A. The measurement equivalence in Japanese and English had not been confirmed in prior studies.


METHODS
We analyzed the 40 CASI items for differential item functioning (DIF) related to test language, as well as self-reported proficiency with written Japanese, age, and educational attainment in two large epidemiologic studies of Japanese-American elderly: the Kame Project (n=1708) and the Honolulu-Asia Aging Study (HAAS; n = 3148). DIF was present if the demographic groups differed in the probability of success on an item, after controlling for their underlying cognitive functioning ability.


RESULTS
While seven CASI items had DIF related to language of testing in Kame (registration of one item; recall of one item; similes; judgment; repeating a phrase; reading and performing a command; and following a three-step instruction), the impact of DIF on participants' scores was minimal. Mean scores for Japanese and English speakers in Kame changed by <0.1 SD after accounting for DIF related to test language. In HAAS, insufficient numbers of participants were tested in Japanese to assess DIF related to test language. In both studies, DIF related to written Japanese proficiency, age, and educational attainment had minimal impact.


CONCLUSIONS
To the extent that DIF could be assessed, the CASI appeared to meet the goal of measuring cognitive function equivalently in Japanese and English. Stratified data collection would be needed to confirm this conclusion. DIF assessment should be used in other studies with multiple language groups to confirm that measures function equivalently or, if not, form scores that account for DIF.
Gibbons
Laura E
LE
Department of Medicine, University of Washington, Seattle, USA. gibbonsl@u.washington.edu
McCurry
Susan
S
Rhoads
Kristoffer
K
Masaki
Kamal
K
White
Lon
L
Borenstein
Amy R
AR
Larson
Eric B
EB
Crane
Paul K
PK
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001076:Aptitude; D001213:Asian / Q000523:psychology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000208:ethnology; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D003704:Dementia / Q000175:diagnosis* / Q000453:epidemiology / Q000208:ethnology; D004522:Educational Status; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data; D019303:Multilingualism; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012737:Sex Factors; D014481:United States